Improvement in apparatus for the manufacture of paper-pulp



UNITED STATES PATENT OFFICE.

JoHN'w. DIXoN, or PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT lN APPARATUS FOR THE MANUFACTURE OF PAPER-PULP.

- Specification forming part of Letters Patent No..52,694, dated February 20, 1866.

il) Il trimm. i t om: 1/ concern.

Be it known that I, JOHN W. DIXornot' the city of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in the Apparatus for Making Wood, Straw, or

Manila Pulp; and Ido hereby declare the fol across the interior of each ot' these boilers'aperforated diaphragm, C, Fig. 1, with an opening through it. covered by a removable perforated cover, D. This is placed about onetenth of the altitude of the boiler below the top. A lower perforated diaphragm', E, is placed in each boiler near the bottom, slightly conical, or tapering downward toward a central opening, F. This open-ing F is connected, by a pipe or tubing, G G, with the exterior pipe for carrying off the contents. Aslide-valve, H, operated by a stem, I, covers this opening F in each boiler, passing through a stufingbox, K. The top of each boiler is surmounted by a cover or. head, L or L', furnished with safety-valves and having a manhole and cover, M.

O is a furnace or vertical fire-chamber, having acoil of pipe, P P', extending through it, Fig. 1, with grate-bars at R, as is usual in furnaces and ilues, and having, also, proper dampers.

A tube, S S' S", extends across in front of the lower part of the two boilers A and B, and is connected with the lower extremity of the coil of tubes P P'. Cocks are placed at N o. l and No. 2, leading, respectively,to boilers A and B. At T a rotary force-pump is placed in the course of the tube S S' S", driven by-an exterior pulley across the top of the boilers, a tube, U U' U", connecting by cocks at 4 and 5 with the upper part of boilers A and B, respectively, and connecting with the top of the coil P P'.

. This apparatus is intended, mainly,to carry out the improved process for which Letters Patent have been heretofore granted to me,

and the operation is as follows: The boiler A is to be chargedwith chipped or cut wood through the man-hole M. The boiler is then to be filled, or partly filled., with a solution of caustic soda-say from '40 to 80 Baume, or thereabouts-the lid l) having been removed from the center ot' the perforated diaphragm C while the wood is being charged, and replaced and buttoncd or latched down before the caustic liquor is poured in. After thesolution ot' alkali has been charged in, the manhole is bolted down. The lire under the coil P in the furnace having been kindled the cock l is opened,' alsocock 4, the other cocks and valves being closed. The pump T is' made t0 revolve by a belt. This pump forces the digesting liquid', strained from thewood fibers from the space below the perforated diaphragm E, up through the coil P, and through the pipe U U' U", and through the open cock 4, to the upper part of the boiler A. This fluid descends through the mass of wood or vegetable brous matter being treated and passes out through cock l and tube S S' S" toward the vertical coil P P', as before. Thus a forced circulation through the boiler and through the heating-coil P P' is constantly maintained, and a much more rapid heating and digesting action is obtained than can be obtained in any other way. The contents of the boiler A are to be heated above 2120. l find the apparatus works well with wood and straw at a pressure of fifty to sixt-y pounds, the requisite pressure being obtained by loading the safetyvalve after the contents of boiler A have been subjected for a sutlicient time to the circulating action, as above described, in order to digest the woody fibers, which time depends on the nature ot' the digesting-liquor, pressure', and'nature of material treated'.

While the contents of boiler A are being thus treated, the boiler B is to-be prepared thus: Itis to be charged with chipped woody matter in the same way as above described for boiler A, the man-hole cover M and diaphragm lid O having been removed for that purpose. An increasedV percentage ot' solution ot' caustic soda-say about twenty per cent. of

the quantity tirst charged into boiler A-is to be charged into this boiler B at a strength ot' from 40 to 8O Baume. The man-hole and covers vare then closed down.

finished digesting,

and No.l 4 is shut, and the liquid contents of One boiler having been thus prepared is operated as follows: As soon as boilerA is the cock No. 5 is'opened boiler A are then drawnoft' from the bottom of A and driven, by the rotary pump T, through the coil P P and pipe U U U,into the top of boiler- B. When the boiler VA is thus emptied of its liquid contentsinto B, cock N o. lis shutv andcock No. 2 is opened, B being thus lled with heated liquid `from A. A is isolated by closing of cocks- .1 and 4. The circulation through the coil and the boiler'B goes on, as vbefore described,lby the aid of the pumps, and

the digested pulpy matter from A is drawn oft' by pulling out the slide-valve H, and can be led oto the-tanks or reservoirs.

While the contents ot boiler B are' being cooked, is t-obe filled with, say, cnt straw, andtlief'lqnid contentsof B are to be'drawn off'and forced# into A by closing valve 5 and opening valve'4, .and when all the liquid contentsof B are forced into A the cock 2 is'to be closed .and cook-1 opened, -by lwhich B becomes isolated, and the slide valve in the lower part of B is to be opened and the pulp or solid contents discharged out.

v'llhis alternate act-ion of the two boilers could be kept up for any length of time` although in my process patent I have described the manner in which I prefer to use the refuse of one operation for a succeeding one.

I do not desire to claim herein the combination ot'upperand lower perforated diaphragm,

lnor the combination of lower diaphragm and desire to secure by Witnesses:

GIIAs. H. WHITE, J. E. MCGAULLEY. 

